Trans-Atlantic correlation of eruptive sequences and individual silicic volcanic units within the Paranل-Etendeka igneous province

The Mesozoic volcanic rocks of the Serra Geral Formation in the Paranل Basin, South America, and of the Etendeka Group in northwestern Namibia were erupted shortly before the opening of the South Atlantic. The major widespread silicic volcanic units in the Etendeka Group are interpreted as rheoignimbrites (Milner et al., 1992) and are interbedded with tholeiitic basalts and basaltic andesites. uthern portion of the Etendeka Group is subdivided into a basal Awahab Formation which is overlain disconformably by the Tafelberg Formation. Both formations contain silicic and mafic units. Bulk composition, initial 87Sr86Sr ratios, phenocryst assemblages and mineral compositions are used to correlate silicic units of the Awahab Formation with the basal units of the Palmas silicic volcanic rocks in the southern Paranل Basin. Silicic units of the Tafelberg Formation can similarly be correlated with silicic units in the upper portion of the Palmas succession, which are also disconformable on the units below them. Not all silicic units in these successions are present in both the Etendeka and Paranل areas, but where correlation of individual units is possible, then this is found to be consistent with the overall stratigraphic sequence. c units in the Awahab Formation were erupted from the Messum Igneous Complex in Namibia and their correlation into Brazil indicates that individual eruptive units must have travelled over 340 km from their source. Serial changes in the composition of silicic units in the Awahab Formation and their correlatives indicates that they were erupted from a single magma system from which a total of ~ 8600 km3 of material was erupted.